Trekon did a real good tutorial if you search his stats.
You can get a lot of answers by doing a google search like this...
how to post pictures site:bushcraftusa(dot)com
I can't help with videos yet, but I'm sure others will chime in to help. Photobucket accounts are free. After you load your pictures, all you do it hover over the image, a small window will open, click on the "copy image" link and paste it into your thread, add your comments and you're set.
If the pic is on you PC go to advanced and click on the arrow next to the paper clip then when the window comes up maximize it and click on browse to locate it. Then double click it and click upload. Then enter your text, click preview to see it and if all's OK click submit. just did 2 of them a few minutes ago.